ons have been
already described. The second is the localization of the function of
thought in the circumvolutions of gray matter on the surface of the
cerebral hemispheres--fact that we have already assumed to be
sufficiently demonstrated. The third class of facts include those, also
insisted upon, that indicate a peculiar influence of the emotions upon
the circulation and the vaso-motor nerves. In some cases these are
stimulated, and the blood-vessels spasmodically contract, the cheek
pales, the hands and feet grow cold, chills creep down the back--even
nausea may occur from interference with the circulation of the brain; or
else the cheek flushes, the temples throb, the heart beats more rapidly,
when, from temporary paralysis of these same nerves, the blood-vessels
are suddenly dilated.

These phenomena indicate that either the anatomical seat or the mode of
generation of emotion, is in closer connection with the cerebral
vaso-motor centre than is the seat of ideas.

From this positive stand-point we may be permitted to cautiously venture
a little further, in the direction of a theory for the precise
localization of the organs of emotion.

It is well known that at the base of the brain are collected certain
masses of nervous matter, that constitute nervous centres or cerebral
ganglia, that are in very intimate connection, on the one hand, with
nerves of special sense, as the optic[42] and olfactory,[43] on the
other with nerves of general sensation and motion.[44] To this intricate
part of the brain, these centres, converge the nerve-fibres collected in
the spinal cord and medulla oblongata, and from them radiate other
fibres that pursue a divergent course, and finally terminate in the gray
matter of the cerebral hemispheres. Thus, the brute impressions brought
from the periphery of the body, are conveyed to special foci of
concentration, thence to be transmitted to the gray matter at the
surface of the brain, and become material for thought. Conversely,
impulses generated in the nerve-cells devoted to the elaboration of
thought, pass through these same intermediate stations before they
acquire sufficient consistency to affect the motor-nerves, and, through
them, the muscular osseous apparatus of the body. Before a sensory
impression can become a thought, or a voluntary impulse express itself
by motion, each must be converged toward these centres, whence it
afterwards radiates, along divergent fibres, directed now